Table View's 'Cellforrow(At:)' Is 'Nil' in Unit Test

cellForRowAtIndexPath nil during unit tests

Instantiate an actual UITableViewController and this works fine.

unable to dequeue a cell with identifier Cell - must register a nib or a class for the identifier or connect a prototype cell in a storyboard

Have you set the Table Cell identifier to "Cell" in your storyboard?

Or have you set the class for the UITableViewController to your class in that scene?

Difference between tableView.cellForRow(at:) and tableView.dataSource?tableView(tableView:cellForRowAt:)

 func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell

This method is used to generate or dequeue the cells as required by tableView. This is not the UITableView member method. Instead, it is a protocol method and another object, which will be a data source, will implement and return the value. So it will always return a cell whether we are unit testing or while debugging the app.

tableView.cellForRow(at:) 

This method is not the generator method. It is a member method of UITableView as a utility method for eg. for getting selected row we use tableView.selectedRow. So it is supposed to return cell for any indexPath.

As we know UITableView doesn't create cells equal to rows drawn. Suppose you wanted to draw 100 rows then UITableView only create few extra cells apart from cells which are visible. So if you pass any indexPath which is not among the visible rows then practically that cell doesn't exist. Because tableview is waiting for you to scroll and reuse the unused cells. So whether you are doing unit testing or working on app it will always show nil for cells which are not visible.

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